The Hottest New Cancer Drugs Depend on Gut Microbes

Immunotherapy doesn’t work for everyone, and a series of new studies might explain why.

Few recent developments have created more excitement in the world of cancer research than the rise of immunotherapy. After decades of frustration, scientists have finally found effective ways of turning the immune system against tumors, with spectacular results. Patients with kidney cancers and melanomas that had spread all over their bodies—diseases that would typically carry dire prognoses—have been cured. Immunotherapy, once a poster child for neglect and failure, has finally come of age.

The same could be said for the human microbiome. The trillions of bacteria and other microbes that share our bodies were ignored for centuries. But recent studies have shined a spotlight onto these multitudes, by showing how important they are, not least in their ability to train and calibrate our immune systems.